Lubricating arrangement for a two-stroke-cycle internal combustion engine



M. MARIK ET AL June 3, 1969 3,447,519 LUBRICATING ARRANGEMENT FOR A Two-sTRoKE-CYCLE L INTERNAL coMBusTloN ENGINE Sheet Filed Dec. l. 1967 3,447,519 -CYCLE V/ M. MARCIK ET AL LUBRICATING ARRANGEMENT FOR A TWO-S June 3, 1969 TROKE INTERNAL COMBUSTION ENGINE She'et Filed Dec. l, 1967 O l O I O aaron-o.

United States Patent O Ritschl, Prague, Czechoslovakia, assignors to JAWA, narodni podnik, Tynec nad Sazavou, Czechoslovakia Filed Dec. 1, 1967, Ser. No. 687,323 Claims priority, application Czechoslovakia, Dec. 3, 1966, 7,700/66 Int. Cl. F02m 25/00; F02b 47/04 U.S. Cl. 123-127 8 Claims ABSTRACT OF THE DISCLOSURE A carburetor 4for a two-stroke-cycle intern-al combustion engine is provided with `a conduit leading to an opening in an edge portion of the throttle valve which later- 'ally `bounds -t-he stream of combustion air through -the carburetor housing. Lubricating oil is fed to the opening separately from the liquid fuel, and is dispersed in the passing stream. The arrangement is applicable to slide valves and to butterfly valves.

Background of the invention This invention relates to a lubricating arrangement for a two-'stroke-cycle intern-al combustion engine, and particularly to :an arrangement in which `the lubricating oil fis fed to the engine dispersed in the fuel mixture.

It is known to admix the lubricating oil for an engine of the type described to the fuel in the 4fuel tank or :to rfeed the oil :into the fuel mixture or its components iby means of a metering pump in response to the engine yload Iand the throttle opening. This invention is more specilically concerned with the last mentioned arrangement.

In known arrangements, the liquid fuel and the oil are separately fed to the fuel system either in the intake manifold or in the carburetor. It is :a common drawback of both arrangements as they were known heretofore that the oil is inadequately dispersed Iin the fuel mixture at least under some operating conditions so that some of the oil does not reach the cylinder surfaces which zare -to be lubricated, lbut is mainly burned to form Ia smoky exhaust gas. Oil which is not fully `atomfized may Ialso clog conduits in the carburetor.

It is the primary object of the invention to feed lubricating oil to the stream of combustion air through the carburetor housing in such fa manner that dispersion of Ithe oil in the air in the form of tine droplets is ensured under all practical operating conditions.

Summary f the invention With [this object land others in view, :as will become `apparent hereinafter, the invention, in one of its aspects, provides a continuous, eircumferentially closed conduit for lubricating oil which extends outward of the carburetor housing and communicates with the air path through the housing through an opening in an edge portion of -the throttle valve which laterally *bounds the air stream.

AOther features and many of the attendant advantages of this invention will readily become apparent from the Ifollowing detailed description of preferred embodiments when considered in connection with the kappended drawing.

Brief description of the drawing In the drawing:

FIG. 1 shows a carburetor of -the invention in elevational section;

3,447,519 Patented June 3, 1969 Description of the preferred embodiments Referring now to the drawing in detail, and initially to FIG. 1, there is seen a carburetor for 1a two-'strokecyole gasoline engine whose housing 8 has a straight tubular portion 48 for ow of a stream of combusti-on air through the carburetor and into the engine, .and ya hollow Iside earm 7 in `which a slide Valve member 12 is guided 'transversely to the `stream of air into land out of the tubular portion 48. The valve 4member 12 is operated by -a bar 49 which extends outward of .the carburetor housing.

A d-uct 10 in the valve mem'ber 12 terminates in an orifice in an edge portion 11 of the valve member which laterally bounds the air stream at the downstream end of the valve member, the orifice `being directed transversely of the tubular portion 48.

A cover 5 closes the `side arm 7, and a bore 4 in the cover 5 is provided `wi-th :a connector 3 whose pass-age 2 connects yan oil feed pipe 1 coming from a non-'illustrated and lconventional metering pump with a pipe 6 in the side arm 7. The pipe 6 is received in the duct 10 in sealing, telescoping engagement. The duct 10, pipe 5, and connector 3 thus form a continuous, circumferentially closed conduit which extends outward of the carburetor housing and to which oil is 'being fed 'by the pipe 1 for transverse discharge into the yair stream in any operating position of the slide valve member 12 during the rectilinear movement of the latter.

The valve member 12 also carries a metering rod 50 which controls Ithe yadmission of gasoline to the tu'bular portion 48 of the carburetor in a conventional manner not itself relevant to lthe invention, land upstream from the edge portion 11.

The lubricating oil is thus discharged into a portion of the fuel-bearing air stream whose cross section is normally restricted, :and whose velocity .and turbulence are Iat maximum values, thus ensuring `dispersion of the lubricant `into line droplets which are carried by the stream into the engine.

The operating principle of the arrangement shown in FIG. l is equally applicable to `a carburetor whose air supply is throttled :by a butterlly valve, as shown in FIGS. 2 and 3. A `circular disc 43 is mounted on Ia shaft 42 for rotation about a turning axis perpendicular lto the axis of a cylindrical tube 51 Whose iiow section is controlled by the disc.

The shaft 42 has an axial bore 41 which is connected with a duct 45 in the disc 43 by a sealing sleeve 44 partly received in the disc and partly in the stationary shaft 42. The duct '45 terminates in an orice in the circumference of the disc 43 which bounds an air stream through the tube 51 in all operating positions of the disc, and restricts the ilow section of the tube in the position of the disc illustrated in FIG. 2.

Another shaft 52 coaxial with the shaft 42 is xedly fastened to the disc 43, and is provided with a radial arm 53 for controlling the throttling edect of the disc. The aforementioned oil feed pipe 1 is sealingly attached to the portion of the shaft 42 which projects from the tube 51.

FIG. 4 shows a modified embodiment of the invention which is identical with that illustrated in FIG. 1 except as specifically described hereinafter. A stationary pipe 13 supplied with lubricating oil and mounted on the cover of a side arm, as described with reference to the pipe 6 in FIG. 1, extends through a bore of the slide valve member 14 with only sufficient clearance not to interfere with the normal, rectilinear, operating movement of the valve member.

The pipe 13 partly extends outward of an orifice in the edge portion of the valve member V14 which laterally bounds the air stream through the carburetor at the downstream end of the member 14, and downstream from the point of fuel admission. In the closed position of the valve member illustrated in FIG, 4, only the axial orifice of the pipe 13 can discharge lubricating oil. When the valve member 14 moves outwardly of the air stream, radial bores 16 in the pipe 13, which face in the direction of the air stream, are exposed and release the oil into the air stream so that the oil is discharged closely adjacent the edge portion 15 of the valve member 14 in all operating positions of the latter. When covered by the inner wall of the valve member, the radial bores 16 are practically sealed.

In the carburetor illustrated in FIG. 5, a flexible metal tube 17 connects a non-illustrated metering pump for lubricating oil with a longitudinal bore 18 in a bar 19 which partly projects from the carburetor housing and is fixedly fastened to a sliding valve member 20 in the carburetor. The valve member 20 throttles the air stream through the carburetor as described with reference to FIG. 1. The valve member 20' is shifted by means of a non-illustrated throttle linkage attached to the portion of the bar 19 which projects from the carburetor housing.

A restricted terminal portion 21 of the bore 1S communicates with a conduit portion 21a formed in the valve member 20 and terminates in the edge portion 22 of the valve member which laterally bounds the air stream through the carburetor.

In the carburetor of FIG. 6 which is equipped with a sliding throttle valve 28, a pipe 24 is fixedly attached to the valve member and moves inwardly and outwardly of the carburetor housing 23 during the rectilinear reciprocating movement of the valve member 28.v A flexible hose 25 connects the bore 29 of the pipe 23 with a lubricant pump, not shown.

The pipe 24 communicates with a coaxial orifice 26 in the edge face 27 of the valve member 28 which laterally bounds the air stream through the carburetor housing 54 at the downstream end of the valve member.

In the carburetor partly seen in FIG. 7, lubricating oil is supplied by a tube 30 to the bore 31 of a nipple 32 on the carburetor housing 33 which is otherwise identical with the housing 8 shown in FIG. 1. The bore 31 communicates with an axial groove 35 in the inner wall of the housing side arm. The wall is sealingly engaged by a corresponding wall of a Valve member 37 having an orifice 36 which travels along the groove 35 during the normal valve movements, and thereby connects the nipple 32 with a duct 38 in the valve member 37 leading to an orifice in the downstream edge 39 of the valve member.

As is best seen by joint consideration of FIGS. 2 and 3, the orifices in the edge portions of all embodiments of the invention are defined and bounded by annular parts of the corresponding valve members and face transversely of the direction of flow of the air stream or fuel mixtures through the carburetors of the invention.

1t should be understood, of course, that the foregoing disclosure relates only to preferred embodiments of the invention, and that it is intended to cover all changes and modifications of the examples of the invention, herein chosen for the purpose of the disclosure, which do not constitute departures from the spirit and scope of the invention set forth in the accompanying claims.

We claim:

1. In a carburetor for a two-stroke-cycle internal combustion engine having `a housing defining a path for a stream of air of combustion, separate means for admitting a liquid fuel and lubricating oil to said path for mixing with said stream, and a throttling valve member arranged in said housing for movement transversely of said stream, a plurality of operative positions, the valve member having an exposed edge portion laterally bounding said stream, the improvement in the means for admitting the lubricating oil to said path |which comprises:

(a) a continuous conduit extending outward of said housing, said edge portion being formed with an opening; and

(b) means for feeding lubricating oil to said conduit,

the conduit communicating with said opening for discharge of said lubricating oil from said opening into said stream.

2. In a carburetor as set forth in claim 1, wherein said conduit has two telescopically engaged tubular portions respectively fixedly fastened to said housing and to said valve member, said movement of the valve member being substantially rectilinear.

3. In a carburetor as set forth in claim 1, said conl duit being connected to said valve member for movement therewith, the movement of the valve member 'being substantially rectilinear, and said conduit moving inward and outward of the housing when the valve member moves transversely of said stream.

4. In a carburetor as set forth in claim 1, said conduit partly projecting outward of said opening in an operative position of said valve member.

5. In a carburetor as set forth in claim 4, wherein the projecting part of said conduit being formed with an aperture facing in the direction of said stream.

6. In a carburetor as set forth in claim 1, a bar member attached to said valve member and extending outward of said housing for actuating said movement of the valve member, said bar member being formed with a bore constituting a portion of said conduit.

7. In a carburetor as set forth in claim 1, said valve member and said housing having respective walls sealingly engaging each other during the movement of the valve member, respective portions of said conduit being formed in said walls and communicating with each other through openings in said walls.

8. In a carburetor as set forth in claim 1, said edge portion having an annular part defining and bounding said opening, the opening facing transversely of said path.

References Cited UNITED STATES PATENTS 1,473,293 11/1923 Houghtaling 123-127 1,617,605 2/ 1927 Peterson 123-127 1,623,053 4/1927 Howard et al 123-127 3,179,099 4/1965 Alt et al 123-127 XR 3,180,329 4/1965 Altet al 123-119 3,208,442 9/1965 Schnegg et al. 123-127 XR 3,212,485 10/1965 Werner et al 123-119 WENDELL E. BURNS, Primary Examiner.

U.S. Cl. X.R. 123-73, 74, 119 

